14 nm FinFET器件单粒子瞬态特性研究

为评估鳍式场效应晶体管（FinFET）的本征抗辐射能力,本文通过三维工艺计算机辅助设计（TCAD）仿真研究了14 nm FinFET工艺的单粒子瞬态（SET）特性。研究结果表明,在不同的线性能量传输（LET）值及不同的入射位置下,FinFET器件具有不同的单粒子敏感性。SET脉冲宽度随LET值的增大而展宽。此外,SET特性与粒子轰击位置的关系呈现出复杂性。对于低LET值（LET≤1 MeV·cm2/mg）,SET特性与重离子的入射位置具有很强的依赖性;对于高LET值（LET＞10 MeV·cm2/mg）,由于加强了衬底的电荷收集,SET特性与粒子轰击位置的依赖性减弱。     

CCD电离辐射效应损伤机理分析

研究了CCD电离辐射引起总剂量效应和瞬态电离效应的损伤机理.分析了总剂量效应导致OCD平带电压和阈值电压漂移、表面暗电流密度增大以及饱和输出电压下降的规律和机理.研究了单粒子瞬态电离辐射导致OCD单粒子瞬态电荷产生的机理,研究了瞬态脉冲电离辐射导致OCD信号电荷损失的机理.     

偏压电荷收集器测量HPIB的原理和实验

介绍了偏压电荷收集器的结构，分析了利用其测量HPIB束流强度的原理，利用KARAT PIC软件模拟了偏压电荷收集器内部的电荷输运过程，模拟结果表明HPIB在偏压电荷收集器内部电荷中和而电流不中和，从而证实了电荷中和假设和这种装置测量HPIB的准确性。另外还分别对几何参数和偏置电压对偏压电荷收集器的影响进行了模拟，在德拜长度范围内，孔径的大小为0．6-0．8mm比较合适，偏压为-800V就可满足峰值能量为500keV HPIB的测量要求，实验验证了偏压大小与离子收集效率之间的关系。     

电流型PWM控制器单粒子脉冲瞬态效应的试验研究

采用理论分析与试验对比的方式,对脉宽调制(Pulse Width Modulation,PWM)控制器的脉冲激光模拟单粒子瞬态(Single Event Transient,SET)效应的等效性进行研究。对常用的电流型PWM控制器采用脉冲激光进行照射试验,通过改变激光能量得到不同条件下的试验数据,并与重离子照射条件下的试验数据进行对比。试验结果证实线状能量传递值LET(Linear Energy Transfer)=65.2 Me V·cm2·mg-1的868.3 Me V Xe重离子与波长1.064μm、能量为1–2 n J的脉冲激光产生的SET效应最为接近。试验结果为采用脉冲激光对同类型PWM控制器进行模拟SET试验提供了数据支撑。     

单粒子瞬态电流脉冲测试技术研究进展

单粒子瞬态（single-eventtransient，SET）电流脉冲测试技术是在重离子微束中非常重要的一种实验测试技术手段，可以用来测量束流入射位置与单粒子瞬态电流脉冲之间关系，给出电流瞬态脉冲参数（如上升时问、衰退时问以及峰高等）的二维分布图，在微米空间尺度和皮秒时间尺度上对电荷产生、传输以及收集的瞬态过程进行研究。     

用于X射线探测的CVD金刚石薄膜探测器

研制了用于X射线测量的化学气相沉积(CVD)金刚石薄膜探测器.该探测器灵敏区直径为15 mm、厚度300 μm,其暗电流在800 V偏压下小于50 pA,且暗电流-电压曲线线性较好.就CVD金刚石探测器对不同能量X射线的响应及脉冲X射线时间响应进行了理论和实验研究.结果表明:该探测器对6～22 keV X射线具有10-4～10-2A·W-1的灵敏度,假设电荷收集效率为39%时,灵敏度的理论值与实验测量值符合较好,探测器的RC时间常数约为1.5 ns;对亚纳秒脉冲X射线的响应上升时间为2～3 ns.     

超短脉冲激光加速质子束的研究

主要研究了激光参数和靶参数对产生质子能量的影响。为了获得尽可能的质子能量,激光参数如下:尽可能高的激光能量;采用P极化偏振光;预脉冲有一最优长度及最优预脉冲与主脉冲强度比;激光垂直入射;采用基频光。靶参数(材料、厚度、结构形状)对产生高能质子能量、产额、方向性有影     

15 TW激光与氮气作用产生稳定电子束的实验研究

利用15 TW激光脉冲，系统研究了基于电离化注入的激光尾波场加速。实验中，研究了等离子体密度、相互作用位置、激光脉宽以及激光能量对电子束的电荷量、发散角、指向性、能量以及产生概率的影响。将约400 mJ、25 fs的激光脉冲聚焦在喷嘴前沿，等离子体密度约9×10¹⁸ cm^-3时，电子的产生概率高达100%，获得了水平（竖直）发散角（6.5±0.5） mrad（（5.3±0.3） mrad）、水平（竖直）指向稳定性±1.2 mrad （±0.7 mrad）、峰值能量（135±8） MeV和电荷量（13.5±2.0） pC（＞50 MeV）的稳定电子束，为其应用奠定了基础。     

单粒子翻转敏感区定位的脉冲激光试验研究

利用脉冲激光单粒子翻转敏感区定位成像系统,对静态随机存储器件IDT71256开展了单粒子翻转敏感区定位的试验研究。为避开器件正面金属层对激光的阻挡,试验采用背面辐照方式进行测试。试验结果表明,存储单元中存储数据类型对器件单粒子翻转的敏感性有较大影响,由测得的单粒子翻转敏感区分布图经处理得到单粒子翻转截面,结果与重离子试验测得的翻转截面数据一致。     

反应堆压力容器下降环腔在有安全注入流动时的瞬态温度变化

在1／10的比例模型上完成了反应堆压力容器下降环腔在有安全注入流动时的瞬态温度变化。实验考察了有一回路流动和无一回路流动对瞬态温度变化的影响。实验证明：无一回路流动时，下降环腔内瞬态温度的变化速度和幅值随安全注入充速的增加而增加；有一回路流动时，下降环腔内瞬态温度的变化幅值比同安全注入流速时无一回路流动的变化幅值要小。     

Cs-Te photocathode RF electron gun for applied research at the Waseda University

A compact electron accelerator based on photo-cathode RF electron gun is under development for applied research at the Waseda University. Higher charge and higher energy are key issues for applications such as pulse radiolysis experiment and laser-Compton X-ray generation. The new RF-gun cavity with cesium telluride (Cs-Te) photo-cathode which has higher quantum efficiency (Q.E.) compared with metal cathodes has been installed. The evaluation of Q.E. of the photo-cathode has been performed and the value obtained is more than 5% at the preparation stage. For understanding the Cs-Te cathode properties and the higher Q.E. operation, fundamental studies by single bunch beam operation have been performed resulting in more than 6 nC bunch charge with a high Q.E. of 2.9%. Additionally, the new RF-gun cavity was improved for obtaining a higher Q value. Higher beam energy, i.e. shunt impedance compared with old type cavity, was observed. The shunt impedance increased by about 20%. These successful results will considerably contribute to the applied research.     

Use of the Hot-Electron Mirror Machine Interem as a High-Z Ion Source

Production of the high-Z charge states in helium, nitrogen, and argon has been measured in the INTEREM device at the Oak Ridge National Laboratory. The INTEREM device contains a hot electron (~500 keV) plasma trapped in a minimum B geometry. The device is of interest because its parameters, electron density and energy, and ion lifetime are consistent with those required for the production of highly charged ions. Ion charge and ion energy spectra were measured independently using an einzel lens type energy analyzer combined with a quadrupole mass filter. For helium, most of the ions were doubly charged under proper operating conditions. For nitrogen, we found the ion yield to be peaked at Q = 4, and under these conditions the yield at Q = 6 was down by a factor of about 20. Energy distribution curves for different charge states show interesting features, from which important information may be inferred about the plasma in INTEREM. Although discrepancies exist in the ion yields we conclude that an INTEREM-like device employing a minimum B geometry and electron cyclotron resonance heating may be expected to be a good high-Z ion source.     

Ge and Ti post-ion acceleration from laser ion source

Laser ion sources (LIS) are employed with success to generate, in vacuum, Ge and Ti ion beams with high current, ion energy, charge states and directivity.Nanoseconds infrared laser pulses, with intensities of the order of 10¹⁰ W/cm², induce high ablation in Ge and Ti targets. Ions are produced in vacuum with energy distribution following the Coulomb–Boltzmann-shifted distribution and they are ejected mainly along the normal to the target surface. The free ion expansion process occurs in a constant-potential chamber placed at 30 kV positive voltage. An electric field of 5 kV/cm was used to accelerate the ions emitted from the plasma at INFN-LNS laser facility. Time-of-flight technique is employed to measure the mean ion energies of the post-accelerated particles. Ion charge states and energy distributions were measured through an ion energy spectrometer.     

Ion Collection from Resonance-Photoionized Plasma by Applying Radio-Frequency Voltage

Ions were collected on electrodes from laser resonance photoionized plasma by applying 2 MHz radiofrequency voltage to the electrodes. It was demonstrated that the ions are collected in a shorter time at the same kinetic energy of the collected ions compared with ion collection by applying DC voltage to the electrode. A simple one-dimensional model was extended for prediction of ion collection times in the cases of applications of not only DC voltage but also radio-frequency voltage. The ion collection times estimated with the simple one-dimensional model agreed with the experimental values in the case of application of radiofrequency voltages as well as DC voltage. Though the experimental conditions such as ion density are far from those of the plant of atomic vapor laser isotope separation (AVLIS), the simple one-dimensional model shows that radio-frequency voltage method is effective under the conditions close to those of the AVLIS plant.     

A review of ion beam induced charge microscopy

Since its development in the early 1990’s, ion beam induced charge (IBIC) microscopy has found widespread applications in many microprobe laboratories for the analysis of microelectronic devices, dislocations, semiconductor radiation detectors, semi-insulating materials, high power transistors, charge-coupled arrays, solar cells, light emitting diodes, and in conjunction with Single Event Upset imaging. Several modalities of the techniques have been developed, such as lateral IBIC and time-resolved IBIC. The theoretical model of IBIC generation and collection has developed from a one-dimensional model of charge drift and diffusion to a detailed model of the motion of ion charge carriers in semiconductors and insulators. This paper reviews the current state-of-the-art of IBIC theory and applications.     

CVD金刚石微剂量仪的辐射优化研究

金刚石材料具有大的能带间隙、快的电荷收集和低的介电常数等，在较恶劣的实验环境下（如对于超大规模的强子对撞机和同步辐射加速器进行近距离、高辐射条件下的信号探测），有望成为常规的硅、砷化镓等探测器的替代品。为了改进金刚石探测器的性能，本文采用5MeV质子对CVD金刚石微剂量仪进行了辐照，并采用侧向微束离子诱导电荷（IBIC）技术分析研究其性能。实验发现：①经46Gy质子辐照后金刚石探测器的收集效率得到了很大的改善；②收集效率和计数的均匀性也得到了提高，尤其是计数的均匀性，在窄条宽很小情况下其均匀性已达95％以上。可见用质子辐照CVD金刚石是提高其性能的有效途径之一。     

Effect of ion position on single-event transient current

Using focused high-energy microbeams of carbon- and oxygen-ions and a high speed, wide bandwidth measurement system, we found a strong dependence of the collected charge and the transient current waveform on the position of ion incidences. Single-event charge is collected by a diffusion mechanism even when the ion strikes a position about 3 4 μm away from the lateral boundary of the p⁺n-junction area.     

Design of an RFQ for direct plasma injection scheme

A high current radio frequency quadrupole (RFQ) is being studied at the Institute of Modern Physics,Chinese Academy of Sciences (IMP,CAS) for the direct plasma injection scheme (DPIS).Because of the strong space charge of beams from laser ion source,the beam dynamics design of the RFQ has been carried out with a new code,which can deal with space charge effectively.The design of the RFQ structure is performed with an electromagnetic simulation code and the determination of parameters of the structure has been done to maximize the shunt impedance when the frequency is kept fixed.The influences of dipole mode effect and flatness on beams were also discussed.     

Determination of key parameters for SEU occurrence using 3-D fullcell SRAM simulations

A 3-D entire SRAM cell, based on a 0.35-μm current CMOS technology, is simulated in this work with a DEVICE simulator. The transient current, resulting from a heavy ion strike in the most sensitive region of the cell, is studied as a function of the LET value, the cell layout and the ion penetration depth. A definition of the critical charge is proposed and two new methods are presented to compute this basic amount of charge only using SPICE simulations. Numerical applications are performed with two different generations of submicron CMOS technologies, including the determination of the sensitive thicknesses     

Ion-beam-induced-charge characterisation of particle detectors

Ion-beam-induced-charge collection (IBIC) in a nuclear microprobe has been used to characterise detectors for the measurement of particles over a median energy range (100 keV–1 MeV). Three standard detector devices have been studied: a PIPS detector with a buried (ion-implanted) junction structure, a Schottky barrier junction device and a PN-junction photodiode. A 2.0 MeV focussed helium ion beam was used to probe the active area of each device with a spatial resolution 1–2 μm, to quantify the thickness of the dead layer, the charge collection response and the reduction in charge collection efficiency induced by ion-beam damage.